1. Field of the Invention
The present invention relates to a construction machine provided with a construction for inserting and removing a boom foot pin such as a hydraulic excavator.
2. Description of the Related Art
The related art will be described with an example of a hydraulic excavator which is a preferred example of the present invention.
An upper rotating body of the hydraulic excavator is provided with an upper frame. A cabin is installed on one of left and right sides (generally on the left side) of the upper frame. A pair of left and right boom attachment frames are provided on the inner side of the upper frame to the cabin (on the middle part in the lateral direction). A base end of the boom (boom foot) is attached to the boom attachment frames by a boom foot pin.
On the opposite side (on the right side) of the upper frame to the cabin, a side cover is provided on a side surface part, and a front cover is provided on a part covering a front surface part and an upper surface part, respectively. In a device chamber covered by both the covers on the front-right side, are installed various devices including a working oil tank.
The boom is attached to and detached from the upper rotating body at the time of transportation of the machine, maintenance and the like. In this case, since the cabin is located on the left side of the boom foot pin as mentioned above, the boom foot pin is inserted and removed only from the right side.
However, on an extended line of an axis of the boom foot pin (hereinafter, referred to as pin insertion and removal line), is located the working oil tank disturbing the insertion and removal of the pin.
Therefore, there are proposed means that a through hole sufficient for inserting and removing the boom foot pin is provided in the working oil tank (Known Technique 1), or, as disclosed in Japanese Patent Laid-Open Nos. Hei10-18347 and 2000-291056, means that the devices such as a tank is installed at a position apart from the pin insertion and removal line in the device chamber so that a pin insertion and removal space is ensured on the pin insertion and removal line (Known Technique 2).
However, in Known Technique 1, with a complicated shape of the working oil tank, troublesome processing and high cost, there is a fear that the tank is damaged when the pin is inserted or removed. Since there are a lot of harmful effects as mentioned, Known Technique 1 is not the best idea.
Meanwhile, according to Known Technique 2, since the devices are not changed, the problem in Known Technique 1 can be solved. However, since the boom foot pin is not supported in the pin insertion and removal space, there occurred new problems that when the pin is inserted and removed (particularly when removed), the boom foot pin is inclined from the pin insertion and removal line and brought into contact with surrounding structures such as hydraulic piping, or the pin is dropped off as soon as removed from the boom attachment frames so that the pin itself and the structures are damaged.